The invention relates to improved apparatus and method for exposing product, including food product, semiconductors, medical products and any product that has an adverse reaction to air, to a controlled environment. More particularly, this invention relates to improved apparatus and process for replacing air in product and/or containers with a desired controlled environment, including inert gas, combinations of gases and other aromas, mists, moisture, etc.
Various products including food product, semiconductor products, medical products, and any other product that has an adverse reaction to air, are packaged in a controlled environment. Various attempts have been made to efficiently package these products in controlled environments using vacuum and/or controlled environments.
Various food products, including bakery goods, meats, fruits, vegetables, etc. are packaged under atmospheric conditions. Many of these products are presented in supermarkets, for example, in cartons or cardboard containers with a plastic or cellophane wrap covering the product.
One problem with this type of packaging is that the goods have a minimum limited shelf life, which for many products is only several days to a week. With bakery goods for example, mold may begin to grow after a few days under atmospheric conditions. Such products obviously cannot be sold or consumed and must be discarded.
Another problem arises with respect to many fruits and vegetables, which continue to ripen and continue their metabolic process under atmospheric conditions. For example, within a few days a banana can become overripe and undesirable to the consumer.
The space available for gassing operations is often limited at many facilities. In general, existing controlled environment systems are often expensive, bulky, and require three phase power, and, accordingly are impractical for use at many of these facilities.
In an effort to alleviate these problems, various attempts have been made to package food in a controlled environment by injecting controlled environment directly into filled containers. A high velocity flow is often necessary to penetrate into the food product. In general, most of these attempts have proved unsuccessful. With bakery goods, for example, the high velocity jets can pull in air and re-contaminate the product, thereby failing to reduce the oxygen to levels that would prevent the normal onset of mold.
Various techniques for removing air in food filling processes are known in the art. Such processes are used, for example, in the packaging of nuts, coffee, powdered milk, cheese puffs, infant formula and various other dry foods. Typically, dry food containers are exposed to a controlled environment flush and/or vacuum for a period of time, subsequent to filling but prior to sealing. The product may also be flushed with a controlled environment prior to filling, or may be flushed after the filling process. When the oxygen has been substantially removed from the food contents therein, the containers are sealed, with or without vacuum. Various techniques are also known for replacing the atmosphere of packaged meat products with a modified atmosphere of carbon dioxide, oxygen and nitrogen, and/or other gases or mixtures of gases to extend shelf life.
A gas flushing apparatus for removing oxygen from food containers is disclosed in U.S. Pat. No. 4,140,159, issued to Domke. A conveyor belt carries the open top containers in a direction of movement directly below a gas flushing device. The gas flushing device supplies controlled environment to the containers in two ways. First, a layer or blanket of low velocity flushing gas is supplied to the entire region immediately above and including the open tops of the containers through a distributing plate having a plurality of small openings. Second, each container is purged using a high velocity flushing gas jet supplied through a plurality of larger jet openings arranged side-by-side in a direction perpendicular to the direction of movement of the food containers. As the containers move forward, in the direction of movement, the steps of controlled environment blanketing followed by jet flushing can be repeated a number of times until sufficient oxygen has been removed from the containers, and from the food contents therein.
One aspect of the apparatus disclosed in Domke is that the flow of gas in a container is constantly changing. The high velocity streams are directed through perpendicular openings in a plate, which creates eddies near the openings causing turbulence which pulls in outside air. As a container moves past the perpendicular row of high velocity jets, the jets are initially directed downward into the container at the leading edge of the container""s open top. As the container moves further forward, the flushing gas is directed into the center and, later, into the trailing edge of the open top, after which the container clears the row of jets before being exposed to the next perpendicular row of jets. The process is repeated as the container passes below the next row of jets.
The apparatus disclosed in Domke is directed at flushing empty containers and, in effect, relies mainly on a dilution process to decrease oxygen levels. One perpendicular row of jets per container pitch is inadequate to efficiently remove air contained in food product.
Constantly changing jet patterns in prior art devices create turbulence above and within the containers, which can cause surrounding air to be pulled into the containers by the jets. This turbulence also imposes a limitation on the speed at which the containers pass below the jets. As the containers move faster beneath the jets, the flow patterns within the containers change faster, and the turbulence increases. Also, at high line speeds, purging gas has more difficulty going down into the containers because of the relatively shorter residence time in contact with each high velocity row. The purging gas also has a greater tendency to remain in the head space above the containers. In addition, a perpendicular arrangement of jets relative to the direction of container travel causes much of the jet to be directed outside the containers, especially when the containers are round. Moreover, the spacing apart of the perpendicular rows may further vary the flow pattern and pull outside air into the containers.
The size of the container and container opening are also factors which may prevent adequate flushing and removal of existing environment inside the container. Medical bottles or vials that may contain medical liquids or powder, such as, for example, antibiotics, may have openings of less than xc2xd inch. To effectively remove the existing environment from these containers, existing gassing systems, for example, as disclosed in U.S. Pat. No. 4,140,159, issued to Domke, are not adequate. It may also be impracticable to use systems with widths, which may be, for example, less than ⅙ inch.
Therefore, it would be desirable to have a gassing system that would replace the air within empty and/or filled containers of various shapes and opening widths with a controlled environment of higher purity which would greatly increase the shelf life of the product.
One aspect of the present invention provides an apparatus for exposing a container traveling along a conveyor to a controlled environment is provided. The apparatus includes an elongated rail and a first elongated gas deflecting member. The elongated rail includes a longitudinally oriented manifold. The longitudinally oriented manifold is adapted to align with a path of the container. The elongated rail also includes at least one inlet opening to receive a controlled environment gas. The first elongated gas deflecting member is positioned adjacent to the manifold. The first elongated gas deflecting member is contoured to deflect a flow of the controlled environment gas exiting the manifold in a direction transverse to the path of the container and substantially into the container.
Another aspect of the present invention provides a method of operating an apparatus for exposing a container traveling along a conveyor to a controlled environment. An elongated rail and a first elongated gas deflecting member is provided. The elongated rail includes a longitudinally oriented manifold. The container is passed along the elongated rail for a predetermined period of time. A controlled environment gas is supplied through each of the at least one inlet openings. The controlled environment gas is then passed through the manifold. Finally, the controlled environment gas is deflected from the manifold by a contour of the first elongated gas deflecting member in a direction transverse to the path of the container and substantially into the container.
Another aspect of the present invention provides a system for exposing a product contained within a container traveling on a conveyor to a controlled environment. The system includes an elongated rail and a first elongated gas deflecting member. The elongated rail includes a longitudinally oriented manifold and at least one inlet opening to receive a controlled environment gas. The longitudinally oriented manifold is adapted to align with a path of the container. The first elongated gas deflecting member is positioned adjacent to the manifold. The first elongated gas deflecting member is contoured to deflect a flow of the controlled environment gas exiting the manifold in a direction transverse to the path of the container and substantially into the container.
The foregoing and other features and advantages of the present invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the present invention, rather than limiting, the scope of the present invention being defined by the appended claims and equivalents thereof.